Electronic cigarette

ABSTRACT

An electronic smoking article includes an outer tube extending in a longitudinal direction, an inner tube within the outer tube and including a pair of opposing slots, a liquid supply comprising a liquid material, a coil heater, a wick and a mouth end insert. The coil heater is located in the inner tube. The coil heater is formed of an iron-free, nickel-chromium alloy and has substantially uniformly spaced windings. The wick is surrounded by the coil heater such that the wick delivers liquid material to the coil heater and the coil heater heats the liquid material to a temperature sufficient to vaporize the liquid material and form an aerosol in the inner tube.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. application Ser. No.15/248,116 filed on Aug. 26, 2016, which is a continuation of U.S.patent application Ser. No. 15/051,001 filed Feb. 23, 2016, which is acontinuation of U.S. patent application Ser. No. 13/741,254 filed onJan. 14, 2014, and claims priority under 35 U.S.C. §119(e) to U.S.Provisional Application No. 61/593,004, filed on Jan. 31, 2012, theentire content of each of which is incorporated herein by referencethereto.

SUMMARY OF SELECTED FEATURES

An electronic cigarette or cigar (collectively “smoking article”) isprovided which includes a heater element which vaporizes liquid materialto produce an aerosol or “vapor”. The heater element preferablycomprises a resistive heater coil, with a wick extending therethrough.The heater coil is constructed in a manner and formed from a materialsuch that the production of hot spots and excessive temperatures areavoided during a puff.

The electronic article preferably includes a mouth end insert thatincludes at least two, diverging outlets to impart a fuller mouthfeelfrom the vapor output. Preferably, the aforementioned multi-ported mouthend insert cooperates with a gasket. Upon being drawn through thegasket, the vapor output enters a space just upstream of the mouthpiecewhich allows the air stream to expand and decelerate before entering thepassages of the mouth piece insert so as to substantially avoidperceptions of “hot” at or about the lips of the “smoker”.

The electronic article preferably includes a metal case portion and aprecision-formed primary, air inlet port at a location along the metalcase portion, preferably along a metal side wall portion of the article.The air inlet port is precision-formed within close tolerances and theair inlet port is sized so as to be the predominating source of pressuredrop along an air pathway of communication between the air inlet and thesource of vapor (the heater). Such arrangement assures that RTD remainsessentially the same from one puff to the next and from one article tothe next. To further enhance consistent performance, RTD of an articleis checked in the course of its manufacture, and corrective measureundertaken, if necessary.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top planar view of an electronic cigarette according to afirst embodiment;

FIG. 2 is a side cross-sectional view of the electronic cigarette shownin FIG. 1;

FIG. 3a is an exploded, perspective view of elements comprising thecartridge section of the electronic cigarette shown in FIG. 1;

FIG. 3b is a detailed view of an air inlet port of the cartridge sectionof the electronic cigarette shown in FIG. 1;

FIG. 4 is a perspective view of the mouth end insert of the electroniccigarette shown in FIG. 1;

FIG. 5 is a cross-sectional view along line A-A of the mouth end insertof FIG. 4;

FIG. 6 is a perspective view of an alternative embodiment of the mouthend insert of the electronic cigarette shown in FIG. 1;

FIG. 7 is a cross-sectional view along line B-B of the mouth end insertof FIG. 6;

FIG. 8 is an enlarged detail view of the heater assembly of theelectronic cigarette shown in FIG. 1;

FIG. 9A is an enlarged view of the inner tube with a heater coil andwick assembly in position prior to positioning of a closure ring;

FIG. 9B is an enlarged view of the inner tube with a heater coil andwick assembly in position after positioning of a closure ring;

FIG. 10 is a cross-sectional view of a third embodiment of a mouth endinsert for use with the electronic cigarette of FIG. 1;

FIG. 11 is an exploded view of the mouth end insert of FIG. 10;

FIG. 12 is a detailed view of an alternative connection arrangementassembly for use with the electronic cigarette of FIG. 1; and

FIG. 13 is a second embodiment of a connector cathode including a notch.

FIGS. 14A, 14B and 14C illustrate a third embodiment of a connectorcathode including angled holes.

FIG. 15 is an illustration of a connector cathode and anode in which theanode is shortened to allow communication with air inlets.

FIG. 16 is a top view of an electronic cigarette including an aromastrip on an outer surface thereof.

FIG. 17 is a perspective view of a fourth embodiment of a mouth endinsert for use with the electronic cigarette.

FIG. 18 is a cross-sectional view of an electronic cigarette accordingto the first embodiment and further including a sleeve assembly.

FIG. 19 is a side-view of an electronic cigarette according to anotherembodiment.

DETAILED DESCRIPTION Electronic Cigarette Layout

Referring to FIGS. 1 and 2, a novel electronic cigarette (article) 60 isprovided and comprises a replaceable cartridge (or first section) 70 anda reusable fixture (or second section) 72, which in the preferredembodiment are coupled together at a threaded connection 205 or by otherconvenience such as a snug-fit, detent, clamp and/or clasp. Generally,the second section 72 includes a puff sensor 16 responsive to air drawninto the second section 72 via an air inlet port 45 adjacent the freeend or tip of the cigarette 60, a battery 1 and control circuitry. Thedisposable first section 70 includes a liquid supply region of 22 ofliquid and a heater 14 that aerosolizes liquid that is drawn from theliquid supply region 22 through a wick 28. Upon completing the threadedconnection 205, the battery 1 is connectable with the electrical heater14 of the first section 70 upon actuation of the puff sensor. Air isdrawn primarily into the first section 70 through one or more air inlets44.

In the preferred embodiment, once the liquid of the cartridge is spent,only the first section 70 is replaced. An alternate arrangement includesa layout where the entire article 60 is disposed once the liquid supplyis depleted. In such case the battery type and other features might beengineered for simplicity and cost-effectiveness, but generally embodiesthe same concepts as in the preferred embodiment in which the secondsection is reused and/or recharged.

In a preferred embodiment, the electronic cigarette 60 is about the samesize as a conventional cigarette. In some embodiments, the electroniccigarette 60 can be about 80 mm to about 110 mm long, preferably about80 mm to about 100 mm long and about 7 mm to about 8 mm in diameter. Forexample, in a preferred embodiment, the electronic cigarette is about 84mm long and has a diameter of about 7.8 mm.

Preferably, at least one adhesive-backed label is applied to the outertube 6. The label completely circumscribes the electronic cigarette 60and can be colored and/or textured to provide the look and/or feel of atraditional cigarette. The label can include holes therein which aresized and positioned so as to prevent blocking of the air inlets 44.

The outer tube 6 and/or the inner tube 62 may be formed of any suitablematerial or combination of materials. Examples of suitable materialsinclude metals, alloys, plastics or composite materials containing oneor more of those materials, or thermoplastics that are suitable for foodor pharmaceutical applications, for example polypropylene,polyetheretherketone (PEEK), ceramic, and polyethylene. Preferably, thematerial is light and non-brittle.

Cartridge Structure

Referring now to FIGS. 1, 2 and 3 the first section 70 includes an outertube (or casing) 6 extending in a longitudinal direction and an innertube (or chimney) 62 coaxially positioned within the outer tube 6.Preferably, a nose portion 61 (see FIG. 3a ) of an upstream gasket (orseal) 15 is fitted into an upstream end portion 65 of the inner tube 62,while at the same time, an outer perimeter 67 of the gasket 15 providesa liquid-tight seal with an interior surface of the outer casing 6. Theupstream gasket 15 also includes a central, longitudinal air passage 20,which opens into an interior of the inner tube 62 that defines a centralchannel 21. A transverse channel 33 at a backside potion of the gasket15 intersects and communicates with the central channel 20 of the gasket15. This channel 33 assures communication between the central channel 20and a space 35 (see FIG. 2) defined between the gasket 15 and a cathodeconnector piece 37. In the preferred embodiment, the piece 37 includes athreaded section for effecting the threaded connection 205.

The cathode connector piece 37 includes opposing notches 38, 38′ aboutits perimeter 39, which, upon insertion of the cathode connector piece37 into the casing 6, are aligned with the location of each of twoRTD-controlling, air inlet ports 44 and 44′ in the outer casing 6. In anembodiment, such alignment may appear as shown in FIG. 3′(Detail). Sucharrangement allows for placement of the ports 44, 44′ close to thethreaded connection 205 without occlusion by the presence of the cathodeconnector piece 37. The arrangement also reinforces the area of ports44, 44′ to facilitate precise drilling of the holes 44, 44′.

Air Inlets and Control of Resistance to Draw

In the preferred embodiment, at least one air inlet 44 is formed in theouter tube 6, preferably adjacent the threaded connection 205 tominimize the chance of a smoker' fingers occluding one of the ports andto control the resistance to draw (RTD) during smoking. Preferably, eachof the RTD controlling, air inlets 44 and 44′ are machined into thecasing 6 with precision tooling such that their diameters are closelycontrolled and replicated from one cigarette 60 to the next during theirmanufacture. Preferably, the air inlets 44 and 44′ are drilled withcarbide drill bits or other high-precision tools and/or techniques. Alsopreferably, the outer tube 6 is formed of metal or metal alloys suchthat the size and shape of the air inlets 44, 44′ is not altered duringmanufacturing operations, packaging and smoking. Thus, the air inlets44, 44′ provide consistent RTD. In the preferred embodiment, the airinlets 44, 44′ are sized and configured such that the electroniccigarette 60 has a RTD in the range of from about 60 mm H₂O to about 150mm H₂O, more preferably about 90 mm H₂O to about 110 mm H₂O, mostpreferably about 100 mm H₂O to about 130 mm H₂O.

The RTD controlling, air inlets 44 and 44′ are the critical orifice(i.e. the smallest orifice along the pathway from the air inlets 44, 44′and the inner passage 21 of the inner tube 62 (where the heater 14aerosolizes liquid). Accordingly, the air inlets 44 and 44′ control thelevel of resistance to draw of the cigarette 60, which may be set at alevel that contributes a drawing experience similar to that of drawingupon a conventional, lit-end cigarette.

Referring specifically to FIG. 1, another aspect of maintaining preciseand reproducible resistance to draw is use of a metallic material in thecasing 6 which is conducive to precision tooling and techniques. Ifanother material is desired for the casing 6 (such as a plastic forpresenting a softer feel), the air inlets 44, 44′ may be instead formedin a metallic plate fixture (or insert) 43 provided at the location ofthe air inlets 44, 44′ so as to maintain the precision of the air inlets44, 44′.

It is envisioned that the metallic plate insert 43 may be included evenin instances where the casing 6 is metallic, in that such arrangementallows the air inlets 44, 44′ to be produced and tested separately(off-line) on a collection of blank metallic plate inserts 43.Advantageously, should any finished metallic plate inserts 43 fail tomeet standards or specifications for air inlet diameter (and RTD), thefailed inserts may be disposed of instead of entire cartridge assemblies(first section) 70.

Referring back to FIG. 1, the metallic plate insert 43 may comprise aseparate piece that becomes affixed to an outer surface of the casing 6or wholly within the casing 6, in which case the outer casing 6 ispreferably provided with an oversized hole, which can be superposed overthe area of the air inlet 44. It is also envisioned that the insertmight be shaped and fitted flush with the contour of the casing 6, usinga snap fit and/or adhesive between the insert and the casing 6 orentirely within (internal of the outer casing 6). Preferably the shapeand the location of the air inlet 44 of the insert 43 has a symmetrysuch that the air inlet 44 remains fully operative whether the insert 43is positioned as shown in FIG. 1 or flipped 180 degrees. Moreover, themetallic plate insert 43 can be provided on an inside surface or on anoutside surface of the outer casing 6. The metallic plate insert 43 canextend fully or partially about a circumference of the cigarette 60.When the metallic plate insert 43 extends partially about thecircumference, multiple metallic plate inserts 43 can be used, eachmetallic plate insert 43 corresponding to a single air inlet 44, 44′.

In the preferred embodiment, the second section 72, includes an airinlet 45 at an upstream end 5 of the cigarette 60, which is sized justsufficient to assure proper operation of the puff sensor 16, locatednearby. Drawing action upon the mouth end insert 8 is communicated tothe air inlet port 45 through central channels provided in the anodepost 47 c of the first section 70 and the anode connection post 47 b ofthe second section 72 and along space 13 between the battery 1 and thecasing of the second section 72. These channels and the port 45 itselfare sized such that the airflow rate there through are much smaller thanthrough the air inlets 44, 44′, so that the impact on RTD is minimizedand consistency in RTD is maintained. For example, each air inlet can beless than about 2.0 mm in width and less than about 1.5 mm in depth. Forexample, each air inlet can be about 0.7 mm to about 0.8 mm in width andabout 0.7 mm to about 0.8 mm in depth. In a preferred embodiment, 95% ofthe air introduced in the cigarette 60 is through the air inlets 44,44′, whereas only 5% of the total air flow enters through the inlet 45at the upstream end 5 of the cigarette 60. Preferably, the ratio isdetermined by making a central channel 34 of the anode post 47 b of thesecond section 72 small enough to impart a pressure drop far greaterthan that of the air inlets 44, 44′. For example, the central channel 34of the anode post 47 b may be sized to impart a pressure drop ofapproximately 2000 mm water (in contrast to a nominal pressure drop of100 mm water from air inlets 44, 44′ combined).

Referring to FIG. 19, in order to maintain consistent RTD in theproduct, a removable protective covering 601 can be applied to the airinlets 44, 44′ to prevent degradation from dirt and dings during,manufacture, packaging shipping and handling at retail and beyond asshown in FIG. 19. To maintain consistent RTD until consumption, acircumferential wrapping or tape 601 may be wrapped about the outercasing 6 at the locations of the air inlets 44, 44′. In the alternativeor in addition, the cigarette 60 may be accompanied with a reusableprotective cover to provide the same or additional protections.

In addition, current manufacturing techniques for electronic cigarettescan be modified to include testing for consistent RTD. In other words,there is a need to couple an understanding of how to achieve consistentRTD in the product (as taught above) with an understanding of how totest for it in the course of manufacturing the product (as taught in thefollowing). Achieving consistent RTD from one electronic cigarette tothe next promotes consistent performance and delivery levels, andenhances smoking experiences by meeting smoker's expectations that adraw upon an electronic cigarette will be akin to drawing upon a lit endcigarette or cigar. The latter may include testing metallic plateinserts 43 prior to installation as previously described; or instead orin addition, testing completed first sections 70 by fastening a nominal,but inactivated second section 72 to a newly produced first section 70to create a benign, inactive test configuration that accuratelyreproduces airflow event, but without risk of heater activation andapplying a predetermined drawing action upon the configuration whilemeasuring pressure drop. By way of non-limiting example, a fullyassembled electronic cigarette may be drawn through the testconfiguration while pressure drop is measured using a PV10 pressure dropinstrument manufactured by Borgwaldt KC of Chesterfield, Va. A suitablepressure drop testing method for electronic cigarettes can be adoptedfrom standard method ISO 6565:2011 entitled “Tobacco and tobaccoproducts—Draw Resistance of Cigarettes and Pressure Drop of FilterRods—Standard Conditions and Measurement”, and applied withinstrumentation capable of measure pressure drop in a working range of50 mmWG (mm water gauge) to 1900 mmWG and a diameter range of 5.0 mm to9.0 mm. The test can be completed in a matter of seconds and theinstrumentation can be calibrated to a range of 50 mmWG to 300 mmWG.

Instead of using an inactivated second section 72, it is envisioned thata releasable test body might be employed to serve the same purpose in abenign (inactive) test configuration. The test body would be configuredto reproduce nominal impact of a real reusable second portion 72 uponRTD, but could be optimized for machine handing and high speed automatedcoupling to and removal from newly produced first sections 70 that areundergoing testing.

The inclusion of a threaded connection 205 does not facilitateautomated, high speed machine handling and execution of the RTD tests.Referring now to Fig.12, an alternative coupling 205′ may includeconnections comprising pins 501 and releasable detents 503 and/ orelectrical bearing surfaces 505 with releasable detents, rotationallocking devices or the like. In the illustrated embodiment, the detent503 cooperates with a raised annulus 509. In the alternative, one ormore biased balls may be used in lieu of or in addition to the raisedannulus 509. Such arrangements facilitate automated machine handling,provide a greater capacity for speedy yet accurate testing of RTD, andfacilitate machine automated execution of RTD testing. It is envisionedthat quality control during the drilling of orifices could include afeedback loop such that the RTD test results are monitored to detecttrends away from specifications so that corrective measures may beundertaken, such as replacement of a worn drill bit.

Referring now to FIGS. 3a and 3b , preferably, the cathode connectorpiece 37 includes opposing notches 38, 38′ about its perimeter 39,which, upon insertion of the cathode connector piece 37 into the outercasing 6, are aligned with the location of each of two or moreRTD-controlling, air inlets 44 and 44′ in the outer casing 6. In someembodiments, more than two air inlets 44, 44′ may be included (e.g.,three, four, five, six, seven, eight, nine, ten or more). Alternatively,a single air inlet 44 can be included. In an embodiment, such alignmentmay appear as shown in FIG. 3b . Such arrangement allows for placementof the air inlets 44, 44′ close to the threaded connection 205 withoutocclusion by the presence of the cathode connector piece 37. Thearrangement also reinforces the area of air inlets 44, 44′, which canserve to facilitate precise drilling of the air inlets 44, 44′. Otherarrangements can also be used as discussed below.

In another embodiment, as shown in FIG. 13, the cathode connector piece37 can include one or more slits 300 formed in the perimeter 39 of thecathode connector piece 37. The outer casing 6 of the cartridge portion70 is slid over the unthreaded end of the connector piece 37 until itreaches the stop (or edge) 307, leaving a predetermined portion of theslit 300 open to the exterior of the cartridge portion 70 for theadmission of air. The admitted air can travel along the slit 300 andinto the interior of the cartridge portion 70. The slit 300 may be usedas the critical orifice and can be used in lieu of air inlets 44 and44′. In another embodiment, the slit 300 may be used in addition to airinlets 44 and 44′.

In yet another embodiment, as shown in FIGS. 14A, 14B and 14C, thecathode connector piece 37 can include one or more angled holes 301formed therein, which communicate with one or more slots 302 in acathode connection fixture 49 b. Preferably, the cathode connectionfixture 49 b can include an empty annular space 303 in an inner portionthereof which communicates with the one or more slots 302. Air is drawnin through slot 302 and travels into the annular space 303 and fromthere into the angled holes 307. Thus, there is no need to line up theslot 302 with the angled hole 301 because air will travel around theannular space 303 and into the angled holes 301 even if the holes 301and slots 302 are not aligned. This arrangement provides advantagesduring manufacture since the angled holes 301 need not be aligned withthe slots 302.

As shown in FIG. 15, in yet another embodiment, the anode post 47 c canbe shortened as compared to the anode post 47 c of FIG. 2 so as toprovide a larger air gap behind the cathode connector piece 37. Airenters via slot 302′ (not shown in FIG. 15 other than its relativeposition) and is drawn through an internal air inlet 44 via annularspace 303 and then flows straight into the air gap, through the centralchannel 34 of the anode post 47 c and into the central channel 20leading to the heater 14.

Liquid Supply Region, Heater and Wick

Preferably, a nose portion 93 of an downstream gasket 10 is fitted intoa downstream end portion 81 of the inner tube 62. An outer perimeter 82of the gasket 10 provides a substantially liquid-tight seal with aninterior surface 97 of the outer casing 6. The downstream gasket 10includes a central channel 84 disposed between the central passage 21 ofthe inner tube 62 and the interior of the mouth end insert 8 and whichcommunicates aerosol from the central passage 21 to the mouth end insert8.

The space defined between the gaskets 10 and 15 and the outer tube 6 andthe inner tube 62 establish the confines of a liquid supply region 22.The liquid supply region 22 comprises a liquid material and optionally aliquid storage medium 210 operable to store the liquid material therein.The liquid storage medium 210 may comprise a winding of cotton gauze orother fibrous material about the inner tube 62.

In the preferred embodiment, the liquid supply region 22 is contained inan outer annulus 620 between inner tube 62 and outer tube 6 and betweenthe gaskets 10 and 15. Thus, the liquid supply region 22 at leastpartially surrounds the central air passage 21. The heater 14 extendstransversely across the central channel 21 between opposing portions ofthe liquid supply region 22.

Preferably, the liquid storage medium 210 is a fibrous materialcomprising cotton, polyethylene, polyester, rayon and combinationsthereof. Preferably, the fibers have a diameter ranging in size fromabout 6 microns to about 15 microns (e.g., about 8 microns to about 12microns or about 9 microns to about 11 microns). The liquid storagemedium 210 can be a sintered, porous or foamed material. Alsopreferably, the fibers are sized to be irrespirable and can have across-section which has a y shape, cross shape, clover shape or anyother suitable shape. In the alternative, the liquid supply region 22may comprise a filled tank lacking a fibrous storage medium 21 andcontaining only liquid material.

Also preferably, the liquid material has a boiling point suitable foruse in the electronic cigarette 60. If the boiling point is too high,the heater 14 will not be able to vaporize liquid in the wick 28.However, if the boiling point is too low, the liquid may vaporize evenwhen the heater 14 is not being activated.

Preferably, the liquid material includes a tobacco-containing materialincluding volatile tobacco flavor compounds which are released from theliquid upon heating. The liquid may also be a tobacco flavor containingmaterial or a nicotine-containing material. Alternatively, or inaddition, the liquid may include a non- tobacco material. For example,the liquid may include water, solvents, ethanol, plant extracts andnatural or artificial flavors. Preferably, the liquid further includesan aerosol former. Examples of suitable aerosol formers are glycerineand propylene glycol.

Referring now also to FIG. 8, in use, liquid material is transferredfrom the liquid supply region 22 and/or liquid storage medium 210 inproximity of the 14 heater by capillary action of the wick 28. In oneembodiment, the wick 28 has a first end portion 29 and a second endportion 31 as shown in FIG. 8. The first end 29 and the second end 31extend into opposite sides of the liquid storage medium 21 for contactwith liquid material contained therein. Also preferably, the heater 14at least partially surrounds a central portion 113 of the wick 28 suchthat when the heater 14 is activated, the liquid in the central portion113 of the wick 28 is vaporized by the heater 14 to form an aerosol. Thewick 28 preferably comprises filaments having a capacity to draw aliquid, more preferably a bundle of glass (or ceramic) filaments andmost preferably a bundle comprising a group of windings of glassfilaments, preferably three of such windings, all which arrangements arecapable of drawing liquid via capillary action via interstitial spacingsbetween the filaments. Preferably, the wick 28 is flexible and includesthree strands, each strand including a plurality of filaments. Moreover,it is noted that the end portions of the 29 and 31 of the wick 28 areflexible and foldable into the confines of the liquid supply region 22.

Advantageously, the liquid material in the liquid supply region 22 isprotected from oxygen (because oxygen cannot generally enter the liquidsupply region 22 via the wick 28). In some embodiments, the liquidmaterial is also protected from light so that the risk of degradation ofthe liquid material is significantly reduced. Thus, a high level ofshelf-life and cleanliness can be maintained.

In the preferred embodiment, the liquid supply region 22 is sized andconfigured to hold enough liquid material such that the electroniccigarette 60 is operable for smoking for at least about 200 seconds,preferably at least about 250 seconds, more preferably at least 300seconds and most preferably at least about 350 seconds. Thus, liquidsupply region 22 is equivalent to about one pack of traditionalcigarettes. Moreover, the electronic cigarette 60 can be configured toallow each puff to last a maximum of about 5 seconds.

Mouth End Insert

Referring to FIGS. 2, 3 a, 4, 5, 6, 7 and 17, the first section 70includes a mouth end insert 8 having at least two diverging outletpassages 24 (e.g., preferably 2 to 6 outlet passages 24, more preferably4 outlet passages 24). Preferably, the outlet passages 24 are locatedoff-axis and are angled outwardly in relation to the central channel 21of the inner tube 62 (i.e., divergently). Also preferably, the mouth endinsert (or flow guide) 8 includes outlets 24 uniformly distributed aboutthe perimeter of mouth end insert 8 so as to substantially uniformlydistribute aerosol in a smoker's mouth during use and create a greaterperception of fullness in the mouth. Thus, as the aerosol passes into asmoker's mouth, the aerosol enters the mouth and moves in differentdirections so as to provide a full mouth feel. In contrast, electroniccigarettes having a single, on-axis orifice tend to direct its aerosolas single jet of greater velocity toward a more limited location withina smoker's mouth.

In addition, the diverging outlet passages 24 are arranged and includeinterior surfaces 83 such that droplets of unaerosolized liquidmaterial, if any, that may be entrained in the aerosol impact theinterior surfaces 83 of the mouth end insert 8 and/or impact portions ofwalls 305 which define the diverging outlet passages 24. As a resultsuch droplets are substantially removed or broken apart, to theenhancement of the aerosol.

In the preferred embodiment, the diverging outlet passages 24 are angledat about 5° to about 60° with respect to the longitudinal axis of theouter tube 6 so as to more completely distribute aerosol throughout amouth of a smoker during use and to remove droplets. In a preferredembodiment, there are four diverging outlet passages 24 each at an angleof about 40° to about 50° with respect to the longitudinal axis of theouter tube 6, more preferably about 40° to about 45° and most preferablyabout 42°.

Preferably, each of the diverging outlet passages 24 has a diameterranging from about 0.015 inch to about 0.090 inch (e.g., about 0.020inch to about 0.040 inch or about 0.028 inch to about 0.038 inch). Thesize of the diverging outlet passages 24 and the number of divergingoutlet passages 24 can be selected to adjust the resistance to draw(RTD) of the electronic cigarette 60, if desired.

In one embodiment shown in FIG. 17, the mouth end insert 8 can includediverging outlet passages 24 and an on-axis outlet passage 26.

As shown in FIG. 2, an interior surface 83 of the mouth end insert 8 cancomprise a generally domed surface 83. Alternatively, as shown in FIG.7, the annular interior surface 83′ of the mouth end insert 8 can begenerally cylindrical or frustoconical, with a planar end surface.Preferably, the interior surface 83 is substantially uniform over thesurface thereof. Moreover, the interior surface 83 can be symmetricalabout the longitudinal axis of the mouth end insert 8. However, in otherembodiments, the interior surface 83 can be irregular and/or have othershapes.

In a preferred embodiment, a hollow 911 is disposed at the convergenceof the diverging outlet passages 24 within the mouth end insert 8

The mouth end insert 8 may be integrally affixed within the tube 6 ofthe cartridge 70.

As mentioned previously, the multi-port mouth end insert 8 disperses andchanges the direction of the aerosol as it is drawn from the electroniccigarette 60 so as to provide a fuller mouth feel. As aerosol is formed,it passes through the central channel 21 in the inner tube 62 andthrough the central channel 84 in the downstream gasket 10. In paneltesting of early prototypes, some panelists reported a “hot” sensationon the lips from smoking an electronic cigarette constructed to includea mouth end insert including a plurality of diverging outlet passages 24and a central channel 84 having a diameter of about 1.3 mm. However, inelectronic cigarettes in which the inside diameter of the centralchannel 84 was increased to about 2.6 mm, reports of “hot” sensationsessentially ceased.

Dynamic modeling of the area at and about the downstream gasket 10 andthe mouth end insert 8 has indicated that a small 1 mm wide centralchannel 84 at the gasket 10 tends to create peak velocities ofapproximately 12 meters per second (m/sec) in aerosol exiting the mouthend insert. In contrast, modeling of a system including a 5 mm widecentral channel 84 indicates peak velocities of only 2.5 m/s is achievedat the exits of the diverging outlet passages 24 of the mouth end insert8, which is approximately a five-fold decrease in air velocity. From theaforementioned testing and modeling it is believed a further improvementin the organoleptic experience with an electronic cigarette is achievedby preventing acceleration of the aerosol flow stream by increasing thediameter of the central channel 84 before it is drawn through the exitsof the diverging outlet passages 24 of the multi-port mouth end insert8.

Accordingly, it is advantageous to provide an electronic cigarettehaving a downstream gasket 10 having a central channel 84, which has adiameter sufficient to prevent acceleration of the aerosol flow streambefore reaching the mouth end insert 8. Preferably, the diameter of thecentral channel 84 is about 2.0 mm to about 3.0 mm, more preferablyabout 2.4 mm to about 2.8 mm. The mouth end insert 8 then divides outputfrom the central channel 84 into multiple divergent streams of reducedspeed so as to provide a full mouth feel and to avoid sensations of“hot”.

In that an appropriately sized central channel 84 of the gasket 10serves to substantially prevent acceleration of the aerosol, suchfunctionality can be further enhanced by providing the exit orifice witha beveled rim (not shown) at its exit plane to further reduce speed ofthe aerosol before it reaches the mouth end insert 8.

In an alternative embodiment, the mouth end insert 8 and the downstreamgasket 10 can be integrally formed as a single piece so as to enhanceconsistent performance and to facilitate manufacture.

As shown in FIGS. 10 and 11, in an alternative embodiment, theelectronic cigarette 60 of FIG. 1 can include a mouth end insert 8having a stationary piece 27 and a rotatable piece 25. Outlets 24, 24′are located in each of the stationary piece 27 and the rotatable piece25. The outlets 24, 24′ match up as shown to allow aerosol to enter asmoker's mouth. However, the rotatable piece 25 can be rotated withinthe mouth end insert 8 so as to at least partially block one or more ofthe outlets 24 in the stationary mouth end insert 28. Thus, the consumercan adjust the amount of aerosol drawn with each puff. The outlets 24,24′ can be formed in the mouth end insert mouth end insert 8 such thatthe outlets 24, 24′ diverge to provide a fuller mouth feel duringinhalation of the aerosol.

Circuitry, Alloys Improving Consistent Heater Performance, Hot Spots andCarbonyl Abatement

In the preferred embodiment, the power supply 1 includes a batteryarranged in the electronic cigarette 60 such that the anode 47 a isdownstream of the cathode 49 a. A battery anode post 47 b of the secondsection 72 preferably contacts the battery anode 47 a.

More specifically, electrical connection between the anode 47 a of thebattery 1 and the heater coil 14 in the first section 70 is establishedthrough a battery anode connection post 47 b in the second section 72 ofthe electronic cigarette 60, an anode post 47 c of the cartridge 70 andan electrical lead 47 d connecting a rim portion of the anode post 47 cwith an electrical lead 109 of the heater element 14 (see FIG. 8).Likewise, electrical connection between the cathode 49 a of the battery1 and the other lead 109′of the heater coil 14 is established throughthe threaded connection 205 between a cathode connection fixture 49 b ofthe second portion 72 and the cathode connector piece 37 of the firstsection 70 and from there through an electrical lead 49 c whichelectrically connects the fixture 37 to the opposite lead 109′ of theheater coil 14.

Preferably, the electrical leads 47 d, 49 c and the heater leads 109,109′ are highly conductive and temperature resistant while the coiledsection 110 of the heater 14 is highly resistive so that heat generationoccurs primarily along the coils 110 of the heater 14. Also preferably,the electrical lead 47 d is connected to the heater lead 109 bycrimping. Likewise, the electrical lead 49 c is connected to the heaterlead 109′ by crimping. In an alternative embodiment, the electricalleads 47 d, 49 c can be attached to the heater leads 109, 109′ viasoldering. Crimping is preferred as it speeds manufacture.

The battery can be a Lithium-ion battery or one of its variants, forexample a Lithium-ion polymer battery. Alternatively, the battery may bea Nickel-metal hydride battery, a Nickel cadmium battery, aLithium-manganese battery, a Lithium-cobalt battery or a fuel cell. Inthat case, preferably, the electronic cigarette 60 is usable by a smokeruntil the energy in the power supply is depleted or in the case oflithium polymer battery, a minimum voltage cut-off level is achieved.

Alternatively, the power supply 1 may be rechargeable and includecircuitry allowing the battery to be chargeable by an external chargingdevice. In that case, preferably the circuitry, when charged, providespower for a pre-determined number of puffs, after which the circuitrymust be re-connected to an external charging device. To recharge theelectronic cigarette 60, an USB charger or other suitable chargerassembly can be used.

Preferably, the electronic cigarette 60 also includes control circuitryincluding a puff sensor 16. The puff sensor 16 is operable to sense anair pressure drop and initiate application of voltage from the powersupply 1 to the heater 14. As shown in FIG. 2, the control circuitry canalso include a heater activation light 48 operable to glow when theheater 14 is activated. Preferably, the heater activation light 48comprises an LED and is at an upstream end of the electronic cigarette60 so that the heater activation light 48 takes on the appearance of aburning coal during a puff. Moreover, the heater activation light 48 canbe arranged to be visible to the smoker. In addition, the heateractivation light 48 can be utilized for cigarette system diagnostics orto indicate that recharging is in progress. The light 48 can also beconfigured such that the smoker can activate and/or deactivate the light48 for privacy, such that the light 48 would not activate during smokingif desired.

Preferably, the at least one air inlet 45 (FIG. 1) is located adjacentthe puff sensor 16, such that the puff sensor 16 senses air flowindicative of a smoker taking a puff and activates the power supply 1and the heater activation light 48 to indicate that the heater 14 isworking.

A control circuit is preferably integrated with the puff sensor 16 andsupplies power to the heater 14 responsive to the puff sensor 16,preferably with a maximum, time-period limiter.

Alternatively, the control circuitry may include a manually operableswitch for a smoker to initiate a puff. The time-period of the electriccurrent supply to the heater may be pre-set depending on the amount ofliquid desired to be vaporized. Alternatively, the circuitry may supplypower to the heater 14 as long as the puff sensor 16 detects a pressuredrop.

Preferably, when activated, the heater 14 heats a portion of the wick 28surrounded by the heater for less than about 10 seconds, more preferablyless than about 7 seconds. Thus, the power cycle (or maximum pufflength) can range in period from about 2 seconds to about 10 seconds(e.g., about 3 seconds to about 9 seconds, about 4 seconds to about 8seconds or about 5 seconds to about 7 seconds).

Preferably, the heater 14 is a wire coil that surrounds the wick 28.Examples of suitable electrically resistive materials include titanium,zirconium, tantalum and metals from the platinum group. Examples ofsuitable metal alloys include stainless steel, nickel-, cobalt-,chromium-, aluminium- titanium- zirconium-, hafnium-, niobium-,molybdenum-, tantalum-, tungsten-, tin-, gallium-, manganese-andiron-containing alloys, and super-alloys based on nickel, iron, cobalt,stainless steel. For example, the heater can be formed of nickelaluminide, a material with a layer of alumina on the surface, ironaluminide and other composite materials, the electrically resistivematerial may optionally be embedded in, encapsulated or coated with aninsulating material or vice-versa, depending on the kinetics of energytransfer and the external physicochemical properties required.Preferably, the heater 14 comprises at least one material selected fromthe group consisting of stainless steel, copper, copper alloys,nickel-chromium alloys, super alloys and combinations thereof. In apreferred embodiment, the heater 14 is formed of nickel-chromium alloysor iron-chromium alloys, although the latter is not preferred forreasons which follow. In another embodiment, the heater 14 can be aceramic heater having an electrically resistive layer on an outsidesurface thereof.

In another embodiment, the heater 14 may be constructed of aniron-aluminide (e.g., FeAl or Fe₃Al), such as those described incommonly owned U.S. Pat. No. 5,595,706 to Sikka et al. filed Dec. 29,1994, or nickel aluminide (e.g., Ni₃Al). Use of iron-aluminide isadvantageous in that iron-aluminide exhibits high resistivity. FeAlexhibits a resistivity of approximately 180 micro-ohms, whereasstainless steel exhibits approximately 50 to 91 micro-ohms. The higherresistivity lowers current draw or load on the power source (battery) 1.

In the preferred embodiment, the heater coil 14 is formed from anickel—chromium alloy that is essentially free of iron content.Experience has indicated that heater coils constructed from an ironchromium alloy suffered oxidation of their iron content if the alloyswere contacted with water during manufacturing operations, duringshelf-life and/or operation of the device.

It is known that heating glycerin and/or propylene glycol beyond certaintemperatures produces carbonyls (which include formaldehydes). Ironoxide tends to catalyze these reactions such that carbonyls are producedat lower temperatures. By using alloys essentially free of iron content,such catalyzation is avoided and the possibility of producing carbonylsand other constituents is minimized.

Moreover, in the manufacture and design of the preferred embodiment,certain aspects and measures are employed to avoid occurrence ofunintended “hot spots” in the heater coil 14 during its heating cycle.Hot spots may contribute excessive peak temperatures that may produceundesired constituents that would otherwise be avoided in the absence ofa hot spot.

While not wishing to be bound by theory, it is believed that if awinding of a coil heater 14 is altered such that spacing between loopsof the coil 14 is locally reduced, the reduced spacing will createhotspots that are believed to drive peak temperatures beyond desirablelevels. It is also believed that establishing uniform spacing along thecoils of the heater 14 and taking steps to preserve the original,uniform spacing in the winding of the coil heater 14 will avoid theconsequences of “hot spots”.

In particular and referring to FIG. 8, it is envisioned that productionof consistent coil spacing 111 throughout the coiled section 110 of agiven heater coil 14 may be achieved in ways including using automatedwinders to wind the coil about the wick 28 and using the wick 28 as anarbor for the winding step. In the preferred embodiment 3 to 8 windingsare preferred, more preferably, 3 to 5 windings.

Once established, the uniformity of the coil spacing 111 is preserved inthe course of manufacture and in the design of the preferred embodiment.

Referring also to FIG. 9A, in particular, the provision of opposingslots 63 in the inner tube 62 facilitates placement of the heater 14 andwick 28 into position within the inner tube 62 without impaction betweenedges of the slots 63 and the coiled section 110 (shown in FIG. 8) ofthe heater 14. Accordingly, edges of the slots 63 are not allowed toimpact and alter the coil spacing 111 of the heater 14, which wouldotherwise create potential sources of hotspots.

Referring now to FIG. 9B, care is taken to position a closure ring 69such that it is proximate to or touches but does not urge against thewick 28. Such positioning avoids imposing bending moments upon theheater coil 14 and avoids bowing of the coil 14 which might otherwiseproduce hotspots along one side of the coil 14 where the coil spacing111 would become compressed and reduced. Thus, the upstream edge 114 ofthe closure ring 69 is brought into proximity of the wick 28, but is notpositioned over the wick 28 so as to avoid the possibility of theaforementioned bowing effect. The closure ring 69, when placed as shownin FIG. 9B, closes off a remainder of open space provided between theheater coil assembly and the slot 63.

In the preferred embodiment, the inner tube 62 and the closure ring 69are constructed from woven fiberglass.

In the preferred embodiment, the inner tube 62 has a diameter of about 4mm and each of the opposing slots 63 has major and minor dimensions ofabout 2 mm by about 4 mm.

In one embodiment, the heater 14 comprises a wire coil which at leastpartially surrounds the wick 28. In that embodiment, preferably the wireis a metal wire and/or the heater coil may extend fully or partiallyalong the length of the wick 28. The heater coil 14 may extend fully orpartially around the circumference of the wick 28. In anotherembodiment, the heater coil is not in contact with the wick 28.

Preferably, the heater 14 heats liquid in the wick 28 by thermalconduction. Alternatively, heat from the heater 14 may be conducted tothe liquid by means of a heat conductive element or the heater 14 maytransfer heat to the incoming ambient air that is drawn through theelectronic cigarette 60 during use, which in turn heats the liquid byconvection.

In one embodiment, the wick 28 comprises a ceramic wick of ceramicfilaments having a capacity to draw a liquid. As noted above, the wick28 is at least partially surrounded by the heater 14. Moreover, in thepreferred embodiment, the wick 28 extends through opposed slots 63 inthe inner tube 62 such that each end of the wick 28 is in contact withthe liquid supply region 22 (shown in FIG. 2).

In the preferred embodiment, the wick 28 comprises filaments andcomprises a bundle of glass filaments. For example, the wick 28 mayinclude a plurality of filaments. The filaments or threads may begenerally aligned in a direction perpendicular (transverse) to thelongitudinal direction of the electronic cigarette. Preferably, the wick28 includes 1 to 8 filaments, more preferably 2 to 6 filaments. In thepreferred embodiment, the wick 28 includes 3 stands, each strandcomprising a plurality of glass filaments twisted together.

In the preferred embodiment, the structure of the wick 28 is formed offilaments through which the liquid can be transported to the heater 14by capillary action. The wick 28 can include filaments having across-section which is generally cross-shaped, clover-shaped, Y-shapedor in any other suitable shape.

Preferably, the wick 28 includes any suitable material or combination ofmaterials. Examples of suitable materials are glass, ceramic- orgraphite-based materials. Moreover, the wick 28 may have any suitablecapillarity drawing action to accommodate aerosol generating liquidshaving different liquid physical properties such as density, viscosity,surface tension and vapor pressure. The capillary properties of the wick28, combined with the properties of the liquid, ensure that the wick 28is always wet in the area of the heater 14 to avoid overheating of theheater 14.

Instead of using a wick 28, the heater 14 can be a porous material whichincorporates a resistance heater formed of a material having a highelectrical resistance capable of generating heat quickly.

Preferably, the wick 28 and the fibrous medium of the liquid supplyregion 22 are constructed from glass fiber.

Sleeve Assembly

As shown in FIG. 18, the electronic cigarette 60 can also include asleeve assembly 87 removably and/or rotatably positioned about a firstsection 70 of the electronic cigarette 70. Moreover, the sleeve assembly87 insulates at least a portion of the first section 70 so as tomaintain the temperature of the aerosol prior to delivery to the smoker.In the preferred embodiment, the sleeve assembly 87 is rotatable aboutthe electronic cigarette 60 and includes spaced apart slots 88 arrangedtransversely about the sleeve assembly such that the slots 88 line upwith the air inlets 44, 44′ in the first section 70 to allow air to passinto the electronic cigarette 60 when a smoker draws a puff. Before orduring smoking, the smoker can rotate the sleeve assembly 87 such thatthe air inlets 44, 44′ are at least partially blocked by the sleeveassembly 87 so as to adjust the resistance to draw and/or ventilation ofthe electronic cigarette 60 if desired.

Preferably, the sleeve assembly 87 is made of silicone or other pliablematerial so as to provide a soft mouthfeel to the smoker. However, thesleeve assembly 87 can be formed in one or more pieces and can be formedof a variety of materials including plastics, metals and combinationsthereof. In a preferred embodiment, the sleeve assembly 87 is a singlepiece formed of silicone. The sleeve assembly 87 can be removed andreused with other electronic cigarettes or can be discarded along withthe first section 70. The sleeve assembly 87 can be any suitable colorand/or can include graphics or other indicia.

Aroma Delivery

As shown in FIG. 11, the electronic cigarette 60 can also include anaroma strip 89 located on an outer surface 91 of at least one of thefirst section 70 and the second section 72. Alternatively, the aromastrip 89 can be located on a portion of the sleeve assembly 87.Preferably, the aroma strip 89 is located between the battery of thedevice and the heater 14 such that the aroma strip 89 is adjacent asmoker's nose during smoking. The aroma strip 89 can include a flavoraroma gel, film or solution including a fragrance material that isreleased before and/or during smoking. In one embodiment, the flavoraroma of the gel, fluid and/or solution can be released by the action ofa puff which may open a vent over the aroma strip when positioned insidethe first section 70 (not shown). Alternatively, heat generated by theheater 14 can cause the release of the aroma.

In one embodiment, the aroma strip 89 can include tobacco flavorextracts. Such an extract can be obtained by grinding tobacco materialto small pieces and extracting with an organic solvent for a few hoursby shaking the mixture. The extract can then be filtered, dried (forexample with sodium sulfate) and concentrated at controlled temperatureand pressure. Alternatively, the extracts can be obtained usingtechniques known in the field of flavor chemistry, such as the SolventAssisted Flavor Extraction (SAFE) distillation technique (Engel et al.1999), which allows separation of the volatile fraction from thenon-volatile fraction. Additionally, pH fractionation andchromatographic methods can be used for further separation and/orisolation of specific compounds. The intensity of the extract can beadjusted by diluting with an organic solvent or water.

The aroma strip 89 can be a polymeric or paper strip to which theextract can be applied, for example, using a paintbrush or byimpregnation. Alternatively, the extract can be encapsulated in a paperring and/or strip and released manually by the smoker, for example bysqueezing during smoking the aroma strip.

In one embodiment, the electronic cigarette 60 of FIGS. 2, 5, 7 and 9can also include a filter segment upstream of the heater 14 and operableto restrict flow of air through the electronic cigarette 60. Theaddition of a filter segment can also aid in adjusting the resistance todraw.

When the word “about” is used in this specification in connection with anumerical value, it is intended that the associated numerical valueinclude a tolerance of±10% around the stated numerical value. Moreover,when reference is made to percentages in this specification, it isintended that those percentages are based on weight, i.e., weightpercentages.

Moreover, when the words “generally” and “substantially” are used inconnection with geometric shapes, it is intended that precision of thegeometric shape is not required but that latitude for the shape iswithin the scope of the disclosure. When used with geometric terms, thewords “generally” and “substantially” are intended to encompass not onlyfeatures which meet the strict definitions but also features whichfairly approximate the strict definitions.

It will now be apparent that a new, improved, and nonobvious electroniccigarette has been described in this specification with sufficientparticularity as to be understood by one of ordinary skill in the art.Moreover, it will be apparent to those skilled in the art that numerousmodifications, variations, substitutions, and equivalents exist forfeatures of the electronic cigarette which do not materially depart fromthe spirit and scope of the invention. Accordingly, it is expresslyintended that all such modifications, variations, substitutions, andequivalents which fall within the spirit and scope of the invention asdefined by the appended claims shall be embraced by the appended claims.

We claim:
 1. A method of manufacturing an electronic smoking articlewherein a wick is surrounded by a coil heater such that the wickdelivers liquid material to the coil heater and the coil heater heatsthe liquid material to a temperature sufficient to vaporize the liquidmaterial and form an essentially carbonyl free aerosol, the methodcomprising: forming a heater coil about a wick, the forming stepincluding establishing coil windings having substantially uniformspacing between each winding; and maintaining the spacing duringmanufacture of the electronic smoking article.